Explosion proof flame trap and drain



March 12, 1957 w. E. PARISH 2,784,741

- EXPLOSION PROOF FLAME TRAP AND DRAIN Filed Aug. 3. 1953 :97 5 wwzwgfldw A TTORNE Y.

2,784,741 EXPLOSION PRODF'IFLAMETRMP AND DRAIN Willard -E. Parish,Syracuse, N. Y., assignor to Crouse- Hinds Company, Syracuse,N. Y acorporation. of New York Application August 3, 1953, Serial No. 371,979

Claims. (Cl. 138-42) This invention relates to a combination flame trapand drain for conduit fittings in electrical systems.

The invention has as an object a device of the type referred toembodying a structural arrangement which is particularly economical tomanufacture and assemble and, when assembled, providing a flame path ofrestricted but uniform dimension to efliciently cool the ignited gases,all whereby in the event the device becomes plugged or clogged it may,because of its exceedingly low cost, be thrown away or disposed of and anew device substituted in its place.

The invention consists in the novel features and in the combinations andconstructions hereinafter set forth and claimed.

'In describing this invention, reference is made to the accompanyingdrawings in which like characters designate corresponding parts in allthe views.

In the drawings- Figure l is a bottom plan view of a flame trap anddrain embodying my invention.

Figure 2 is a vertical sectional view taken on line 2-2, Figure 1.

Figure 3 is a view taken on line 3-3, Figure 2.

The device consists of a cylindrical body member 10, the outer endportion 11 of which is of slightly greater dimension and having aperiphery of hexagonal formation. The inner portion of the body isthreaded externally for attachment to a conduit fitting 12. The purposeof the hexagonal head portion 11 is for application of a wrench totighten the drain into the conduit fitting.

The body is formed with an axial bore extending inwardly from the innerend of the body and communicating with a radial or transverselyextending passage 13 formed in the outer end portion of the body. Aseries of cup-shaped members 14 are arranged in the bore in stackformation, and the bottom wall of each of the cup-shaped members isformed with an aperture 15.

A disk 16 is positioned in each of the cup-shaped members 14. Thesedisks are i-mperforate and are provided with means for centering thedisks axially in the cupshaped members. Preferably, the disks 16 areformed on each side with a plurality of projections 17. The disks 16 arematerially greater in diameter than the apertures formed in the bottomwalls of the cup-shaped members.

nited States Patent 0 The disks are of polygonal form and dimensioned sothat v the points 18 of the polygon engage, or are in close proximityto, the inner surfaces of the flanges of the cup-shaped members, wherebythe spaces 19 between the sides of the polygon and the flange of thecup-shaped members provide a number of paths through which the explodedgases may travel outwardly from within the fitting 12. The projections17 may be conveniently formed by pressing dimples into the diskssimultaneously with the blanking of the disks from sheet metal.

The innermost cup-shaped member is closed by a washer 21 which isengaged by a radial flange 22 formed on a tubular member 23. The flangeof the tubular member is maintained against the stack formation by asnap ring 'ice 24 engaging the inner side of the flange 22 and beingpositioned in a circular groove formed in the bore ofthe body.

Preferably, the inner portion of the body bore is of increased diameteras indicated at 25,. the space between the tubular member 23 and theinner end of the bore forming a well for theaccumulation of dirt andsludge which otherwise might be carried into the stack formation andcause the space between the disks 16 and the cup shaped members tobecome clogged.

The outer end portion of the body is encircled by a band 26 arranged inregistration with the radial passage 13 and spaced outwardly therefrom,the lower edge of the band terminating remote from the enlarged headportion 11 to provide a circular discharge opening for the escape ofgases. The purpose of the band 26 is to lessen the possibility of theradial passage 13 becoming plugged up, as by the device being painted.

As constructed, the body of the fitting is formed by a simple screwmachine operation. The cup-shaped members 14 and the disks 16 are mosteconomically produced by punch press operation. Due to the polygonalshape of the disks 16 and the projections 17, the disks are centeredboth radially and axially in the cup-shaped members to provide a passageof uniform area for the escaping gases, thus eliminating any inaccuracyin the: assemblage of the parts. This device, because of its novelstructural arrangement, can be manufactured at a cost of a few centswhereby, in the event that the device does become wholly or partlyclogged, it can be thrown away and a new device substituted in itsplace. This avoids labor time in disassembling and cleaning the deviceand eitects assurance of a properly operating device.

What I claim is:

1. A combination flame trap and drain for electric conduit fittingscomprising a body adapted for flame tight attachment to a conduitfitting, said body being formed with an axial bore extending outwardlyfrom the inner end of the body, the outer end portion of the body beingformed with a radially extending passage communicating with the outerend of said bore, a series of cup-shaped members arranged in stackformation in said bore and with their cylindrical flange portionsengaging the side wall bore, each of said cup-shaped members having anaperture in the bottom wall thereof, an imperforate disk positioned ineach of said cup'shaped members, said disks being substantiallycomplemental in diameter to the in ternal diameter of the flanges ofsaid cup-shaped members, each of said disks being formed with aplurality of projections on each side, and having at least a part of itsperipheral portion spaced inwardly from the flange of the cap-shapedmember in which it is positioned, and means operable to retain saidstack formation in said bore.

2. A device as defined in claim 1 wherein the diameter of said disks isgreater than the diameter of the apertures formed in the cup-shapedmembers.

3. A device as defined in claim 1 wherein the disks are of polygonalshape.

4. A device as defined in claim 1 having a band encircling the outer endportion of the body in registration with said radial passage and beingspaced radially outward therefrom.

5. A combination flame trap and drain for electric conduit fittingscomprising a cylindrical body member extcrnally threaded at its innerend for attachment to a conduit fitting, said body being formed with anaxial bore extending outwardly from the inner end of the body andcommunicating with a radial passage formed in the outer end portion ofthe body, a series of cup-shaped members positioned in said bore instack formation, each of said cup-shaped members being formed with acentral aperture in the bottom wall thereof, a baffle disk positioned ineach jections on their peripheries engaging the side Walls of 5 saidcup-shaped members, a tubular member positioned in the inner portion ofsaid bore and being formed with a radial flange engaging the inner endof said stack formation, and means carried by the body for holding the 1flange of said tubular member against the stack formation.

UNITED STATES PATENTS Armstrong Dec. 6, 1910 Finney et a1 Apr. 9, 1918Calhoun Nov. 12, 1929 Wiggins Oct 6, 1931 Watts Feb. 26, 1952 FOREIGNPATENTS Germany Dec. 30, 1898 Great Britain Mar. 1, 1940

